diff --git a/CHANGELOG.txt b/CHANGELOG.txt
index 1eb12268..30e09672 100644
--- a/CHANGELOG.txt
+++ b/CHANGELOG.txt
@@ -1,3 +1,13 @@
+2026-03-27
+fix: remove duplicate sync_connect option from Phoenix.PubSub.Redis configuration
+  - Phoenix.PubSub.Redis 3.1.0 automatically appends sync_connect: true to redis_opts
+  - Our configuration also passed sync_connect: false, creating a duplicate key
+  - NimbleOptions rejects duplicate keys, causing ValidationError crash on startup
+  - Removed sync_connect from our config - let phoenix_pubsub_redis control it
+  - Fixes production pod crash: "unknown options [:sync_connect], valid options are: [...]"
+  - This completes the phoenix_pubsub_redis 3.1.0 migration started in previous commit
+  Files: lib/towerops/application.ex (redis_pubsub_config/0)
+
 2026-03-27
 fix: update Phoenix.PubSub.Redis configuration for 3.1.0 compatibility
   - Fixed NimbleOptions.ValidationError crash on production pod startup
diff --git a/lib/towerops/application.ex b/lib/towerops/application.ex
index c05a076a..3380c02a 100644
--- a/lib/towerops/application.ex
+++ b/lib/towerops/application.ex
@@ -257,9 +257,8 @@ defmodule Towerops.Application do
       backoff_initial: 500,
       backoff_max: 30_000,
       # Don't exit process on disconnection - let PubSub handle it
-      exit_on_disconnection: false,
-      # Sync connect to fail fast if Redis unavailable at startup
-      sync_connect: false
+      exit_on_disconnection: false
+      # Note: sync_connect is automatically set to true by phoenix_pubsub_redis 3.1.0
     ]
 
     # Add password if configured (read from application config set by runtime.exs)